Continuing the Heinlein-rereading project. Yes, I found the edition I own for sale at Amazon: a 60¢ Pyramid paperback, purchased circa 1968. It joins together two very different novellas Heinlein wrote pre-WW2, one sorta-straight science fiction, the other fantasy. I understand Heinlein was bemused that his publisher stuck them together in a single volume, but he was pragmatic enough to shrug it off and endorse the checks.
"Waldo" is the sorta-straight-SF one. I remember being more impressed with it when I was a young 'un. Nowadays, I really liked the first couple pages, and the last couple pages—I think they're really touching and well-written—-and everything in between, meh.
The problem is that a key component of civilization, DeKalb power receptors, are failing for some unknown reason. The corporation that owns the technology has no option but to go, hat in hand, to Waldo Farthingwaite-Jones, a genius reclusive scientist/inventor. Waldo is afflicted with myasthenia gravis, leaving him weaker than a baby. Fortunately, his immense wealth allows him to establish a home in geosynchronous Earth orbit. The solution to the puzzle involves a lot of tedious pseudo-scientific handwaving.
"Magic, Inc." imagines a (then) near future where the magical laws have been "discovered" and tacked on to normal reality. The adventures of Archie Fraser, building contractor, are followed; his own need of magical services is limited, but that doesn't stop a shady character from coming by to offer them exclusively. In exchange for not having Archie's business burned down.
Archie refuses, and his business is burned down.
Then follows an involved, long process that I didn't follow too closely, because I didn't care enough. But the climax involves travelling to the "Half World", the source of magical power, with a retinue of allies to confront the demon in charge of the mischief.
Imagining the "Half World" as a member of the multiverse where the physical laws are different enough to allow "magic" — gee, that's almost science.